Old 03-29-11, 11:12 AM
  #8  
BCRider
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Location: The 'Wack, BC, Canada
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Bikes: Norco (2), Miyata, Canondale, Soma, Redline

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The "out of round" bit mentioned above is just the typical mechanical tolerances found in the bike's gearing. On a true single speed or fixie the small amounts of this out of roundness due to various tolerance build ups gives you a a few spots where every few crank rotations the chain actually goes quite tight if you don't give it just a little slack.

In your emergency situation any combination that will actually let you install the chain is likely to be fine. But if it should come up you want a combo that has a touch of slack rather than one that is guitar string tight.

And as mentioned already you don't need a spare chain. The one on the bike has more than enough to build a single speed chain from to get you out of the woods or over the hill. In fact I'd say that you'd be fine without even having a small section of a few spare links. It's hard to imagine ripping the chain apart enough to ruin enough that there would not be enough to join to get back.

Note that you'll be cutting and joining the chain on the road/trail in an emergency situation. As such you'll likely be using the original pins re-installed. This is generally not seen as being a good way to do things as such links will never be as strong as originally. The solution for this is to either bring along a half dozen servicing pins if it's a Shimano chain or a few master links if it's a SRAM or KMC. Having those will give you what you need to put back together even a badly damaged chain that got torn and mutilated in even two spots. On the other hand I remember a time on my single speed commuter where I "temporarily" joined a chain using an original pushed out pin and then ended up riding the darn thing for about a month before I remembered to get around to the shop and buy a new chain for it. So re-using a pin and link isn't automatically a recipe for instant disaster.
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